Tropical Storm Debby has killed at least five people as it churns across the US East, where it’s expected to inflict $1 billion or more in damage and losses.

One reason for the storm’s destructive power: It’s moving very slowly.

Although Debby came ashore with hurricane-strength winds, its rainfall — forecast to exceed two feet in some areas — is even more dangerous.

The St. Marys River in northern Florida rose more than 10 feet in one day, while New York will likely see downpours from Debby later in the week. Homes, businesses and farms may be deluged, putting crops and infrastructure at risk.